linux-kernel - Re: [PATCH 4/7] media: hantro: move postproc enablement for old cores

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Date:   Thu, 25 Nov 2021 20:21:41 +0100
From:   Jernej Škrabec <jernej.skrabec@...il.com>
To:     Ezequiel Garcia <ezequiel@...guardiasur.com.ar>
Cc:     linux-media@...r.kernel.org, nicolas.dufresne@...labora.com,
        mchehab@...nel.org, robh+dt@...nel.org, mripard@...nel.org,
        wens@...e.org, p.zabel@...gutronix.de, andrzej.p@...labora.com,
        gregkh@...uxfoundation.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
        linux-kernel@...r.kernel.org, linux-staging@...ts.linux.dev
Subject: Re: [PATCH 4/7] media: hantro: move postproc enablement for old cores

Hi Ezequiel,

Dne četrtek, 25. november 2021 ob 13:00:24 CET je Ezequiel Garcia napisal(a):
> Hi Jernej,
> 
> On Mon, Nov 22, 2021 at 07:46:59PM +0100, Jernej Skrabec wrote:
> > Older G2 cores, like that in Allwinner H6, seem to have issue with
> > latching postproc register values if this is first thing done in job.
> > Moving that to the end solves the issue.
> 
> Any idea what exact register should be written before the post-processor
> is enabled, for H6 to work? Also, which of the PP registers need
> to be written "at the end"?

No, there is too much registers to determine this exactly. Vendor library 
actually stores register values in buffer and write them all at once in 
increasing order. This is probably the reason why HDL engineers missed this 
issue...

> 
> > Signed-off-by: Jernej Skrabec <jernej.skrabec@...il.com>
> > ---
> > 
> >  drivers/staging/media/hantro/hantro_drv.c | 9 ++++++++-
> >  1 file changed, 8 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/staging/media/hantro/hantro_drv.c
> > b/drivers/staging/media/hantro/hantro_drv.c index
> > 8c3de31f51b3..530994ab3024 100644
> > --- a/drivers/staging/media/hantro/hantro_drv.c
> > +++ b/drivers/staging/media/hantro/hantro_drv.c
> > @@ -130,7 +130,7 @@ void hantro_start_prepare_run(struct hantro_ctx *ctx)
> > 
> >  	v4l2_ctrl_request_setup(src_buf->vb2_buf.req_obj.req,
> >  	
> >  				&ctx->ctrl_handler);
> > 
> > -	if (!ctx->is_encoder) {
> > +	if (!ctx->is_encoder && !ctx->dev->variant->legacy_regs) {
> 
> To make this less fragile, do you think it would make sense to
> have a dedicated quirk flag, something like "legacy_post_proc",
> instead of overloading the meaning of legacy_regs.

Sure, it can be done :) But then I suggest "late_post_proc" - it better 
describes what it does.

Best regards,
Jernej

> 
> What do you think?
> 
> Thanks,
> Ezequiel
> 
> >  		if (hantro_needs_postproc(ctx, ctx->vpu_dst_fmt))
> >  		
> >  			hantro_postproc_enable(ctx);
> >  		
> >  		else
> > 
> > @@ -142,6 +142,13 @@ void hantro_end_prepare_run(struct hantro_ctx *ctx)
> > 
> >  {
> >  
> >  	struct vb2_v4l2_buffer *src_buf;
> > 
> > +	if (ctx->dev->variant->legacy_regs && !ctx->is_encoder) {
> > +		if (hantro_needs_postproc(ctx, ctx->vpu_dst_fmt))
> > +			hantro_postproc_enable(ctx);
> > +		else
> > +			hantro_postproc_disable(ctx);
> > +	}
> > +
> > 
> >  	src_buf = hantro_get_src_buf(ctx);
> >  	v4l2_ctrl_request_complete(src_buf->vb2_buf.req_obj.req,
> >  	
> >  				   &ctx->ctrl_handler);